Automatic musical instrument



Oct. 30, 1928 1,689,250

, C. F. STODDARD AUTOMATIC MUSICAL INSTRUMENT Filed April 21, 1924 awwwto'c Charles F isloao ara. A Qua/mugs g M fl-- Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

CHARLES F. STODDARD, OF NEW YORK, N.

Y., ASSIGNOR '10 AMERICAN PIANO COM- PANY, OF NEW YORK, N. Y., A COBPORATIQN OF NEW JERSEY.

AUTOMATIC M'USIECAL Application filed April 21,

This invention relates to automatic musical instrun'ients such for instance as pianos; and it pertains more particularly to expression devices for such instruments, or to means for governing playing intensities.

Among other objects, the invention is intended to provide apparatus capable of reproducing with great fidelity the manual per tormances of pianists and to reenact interpre tations of musical compositions as renderd by well known artists of ability.

It is an object of this invention not only to reproduce accurately the various gradations of dynamic force with which the notes of a musical composition are sounded, but also to reflect the mood and spirit of the manual performer. and thereby to give life and con trast to the mechanical rendition which shall make it approximate manual rendition even more closely than has been possible before.

Other objects and advantages of the invcntion will appear hereinafter.

F or illustration, the accompanying drawings show one practical embodiment of the invention employing suitable pneumatically governed devices in cooperation with a piano acton; but, as will appear to those skilled in the art, the invention is susceptible of embodiment in various constructions and organiza tions other than that particularly shown and described herein. It will -appear likewise that it is not indispensable that all the features or the invention be used conjointly since their respective substantial advantages may accrue from their separate application in any practicable manner to a suitable playing instrument.

The figure is a semi-diagrammatic view of an apparatus embodying the invention.

Referring to the drawings, a player action chest 3 is provided comprising the usual player Pneumatics, valves and ducts, not illus trated, for controlling the same. A wind trunk 7 connects the exhaust chest 3 with the wind chest 12 which may be referred to as the regulated wind chest. A wind chest 14, which may be known as the high exhaust chest, is arranged for communication with the chest 12, and may also beconnected by a wind trunk 5' with a source 01 pneumatic exhaust 6 of any usual or desired construction.

It is to be understood in the following descripton that where the term pressure is INSTRUMENT. I

1924. Serial NO. 707,798.

used, prcssuresin their absolute sense is referred tothat is, relative to zero pressure or absolute vacuum as a base. However, due to the fact that sub-atmospheric pressures are commonly measuredon a water gauge, which assumes atmospheric pressure as a base value, the term exhaust will be used at timesto avoid confusion, in its norn'ial sense of vac uum of sub-atmospheric pressure. Thus, high exhaust is high vacuum, or low pressure and as exhaust increases pressure decreases and conversely.

In the illustrative apparatus ot the drawings, the striker pneumatics of the windchest 8 may be operated by the exhaust in the regulated exhaust chest 12. In order to vary the blow struck by the striker pneun'iatics to thereby vary playing intensities, this regulated exhaust may be varied by subjecting it more or less to the influence of high exhaust in chest 14. F or this purpose there has been provided between the high exhaust chest 14 and the regulated exhaust chest 12 a passage 8 controlled by the throttle valve 9.

F or purposes of simplicity of description, a single regulated exhaust chest has been illustrated which controls pressures throughout the action chest of the piano. As will'be understood by those skilled in the art, however, the action chest of automatic musical instrui'nents is frequently divided into bass and treble sections, in which case a separate regulated exhaust chest and controlling valves and pneumatics may be provided for each section in the usual manner.

The valve 9 may be operated by a variety of ditterent means. In this specific apparatus there has been selected for purposes of illustration the apparatus disclosed in the accompanying drawings now to be described. The valve 9 may be conveniently mounted on a stem passing through the upper wall 0% the exhaust chest 14 previously described. The valve stem is pivotally connected at 10 to the bar 11 which may be connected at one of its ends to a so-called accordion bellows 15 con sisting of a plurality of separate bellows a, b, c and (Z secured together in a stack, one on top of another, the top board of the stack being secured to a fixed support A. Each of the bellows has a different extent of collapse, as for instance the bellows cl may have the greatest extent 0t collapse and the bellows c, o, and a may have progressively decreasing extents of collapse. Each of the separate bellows ot the accordion bellows is separately connected to valve boxes 17 by which the sections of the accordion bellows are controlled. The said valve boxes may be of any of the conventional types commonly employed in the art and may be of the primary type illustrated at page 19 of The Player Piano Upto-Date by William Braid White, published 1914 by Edward Lyman Bill, or may be of the primary or second ary type illustrated at page 49 of the same volume, or may be of the lock valve type illustrated in Stoddard Patent No. 1,409,4l'l9 of March 14:, 1922, or may be of any similar type depending upon the particular conditions to be met. The valve b02188 are connected by suitable tubing 16 to tracker ducts 2 2, 2 and 2 in the tracker bar 2. A spring 18 is also connected to the bar 11 to maintain the accordion bellows normally in expanded position. The spring is not of sufficientstrength, however, to ei'lect opening movement of the accordion bellows when the sections thereof are subjected. to exhaust.

The opposite end ot the bar 11 is pivotally connected to a link 19 which .i s pivot-ally connected to an extension of the movable teat 20 of the pneumatic 21. Pneumatic 21 is connected to the regulateiil exhaust chest 1 by a wind trunk 22. The movable leat 20 has attached thereto a regulator spring 23 which constantly urges it in an upward direction with a force depending on the extent to which the spring is stretched. As will be understood, as the pneumatic 21 is collapsed and the spring is stretched, the force urging the pneumatic to open is increased and vice versa.

Assuming for the moment that the accordion bellows 15 remains fixed in open position under the influence of the spring 18, the function of the pneumatic 21 and spring 23 in controlling the valve 9 may now be considered. Primarily this structure serves to maintain a substantially even tension in the regulated exhaust chest 12 regardless of the number of notes being sounded at any given time by the player action. For instance, if a piano is in operation and the valve 9 is being maintained in substantial equilibrium under the opposed forces acting on it, it a large number of player pneumatics are suddenly operated simultaneously, a large inrush of atmospheric air to the regulated exhaust chest 12 will result. This inrush of air will tend to reduce the exhaust ot the regulated exhaust chest and the pneumatic 21 will, therefore, tend to expand under the influence of its spring, thus permitting the valve 9 to move further away from its seat. An additional quantity of air may, therefore, be drawn from the regulated exhaust chest 12 by the pump. This withdraw in turn would tend to increase the exhaust in the regulated exhaust chest and the pncu matic 21 would tend to collapse, thus again restoring the valve 9 to equilibrium. A reverse condition would, of course, result in a reverse action, as tor instance, it less than the usual number of pneumatics are operated at any given time, the tension in the regulated exhaust chest would tend to increase and the pneumatic 21 would tend to collapse thereby drawing the valve 9 closer to its seat and permitting less air to be withdrawn from the regulated exhaust chest by the pump. This in turn would tend to decrease the tension in the regulated exhaust chest and the pneumatic 21 would tend to expand, thus again restoring the valve 9 to equilibriun'i.

in the apparatus illustrated, however, another factor affecting the valve 9 must be considered. As will be observed, the alve 9 is what may be termed an unbalanced valve, is, the valve area itself is subjected to high exhaust, tending to pull the valve away from its seat and to regulated exhaust tending to pull the valve toward its seat. Since high exhaust is always greater than regulated exhaust, the resultant is an upward pull on the valve. If it be assumed that high exhaust be maintained substantially constant, it will be observed that this diilerential between regulated and high exhaust pulling iuiwardly on the valve assists in the regula tion performed by the pneumatic 21, since, it the differential increases, an incre sed upward pull results tending to decrease the differential, while it the differential decreases, the upward pull decreases, which in turn tends to increase the differential.

Thus far it has been assumed that the ac cordiou bellows remains in fixed position. As will be observed by those skilled in the art, however, -s accordion bellows may be movedv and controlled by applying exhaust, prete ably high t-chaust, to the interior of the sections of the bellows in the manner set forth and descr bed in patent to J. H. Dickinson, No. 1,444,832, patented February 13, 1923.

As in the above mentioned patent, if the accordion bellows or any of the sections thereof are collapsed, an opening movement of the valve 9 results and additional air is withdrawn from the regulated exhaust chest, t iereby tending to increase the tension there in. This results, however, in a partial collapse oi the pneumatic 21 against the tension of its spring 28, the final result being an increase in the tension of the spring 2?, and an increase toe exhaust governed thereby in pneumat'c 21 and the regulated exhaust chest 12. As will be apparent, however. the pneumatic 21 will o crate to maintain the new degree oi exhaust substantially constant as h tore whatever the number of notes being sounded simultaneously.

To sum up, the apparatus thus far described produces automatically incremental changes in playing intensities, and it perlilo forms a regulating function-that is, it 1naintains any given playing intensity whether one or many notes be sounded.

In the present description it has been assumed thus far that the degree of exhaust produced by the main source of power re mains substantially constant. the aforementioned patent, indeed, it was innnateria] whether the exhaust produced by the main source of power remained constant or not in so far as the valve 9 was concerned since changes in the degree of exhaust have no etfeot upon the valve 9 in the patent since this valve was of the knife valve or balanced valve type. In the present apparatus, however, the pressure produced by the source of power and maintained in the high exhaust chest 14 is of material importance, because, as explained before, the degree of exhaust main tained in the high exhaust chest 14; is one of the factors affecting the valve 9 to thereby govern playing intensities. This feature has been taken advantage of to increase the capacity of the present apparatus to producevariations in playing intensi ies beyond that of the apparatus of the patent, and to thereby render it more effective in reproducing with fidelity and accuracy the performances at artists of ability.

F or this purpose it is proposed to deliberately vary the pressure maintained in the high exhaust chest by the source of power when desired and also to maintain it at a substantially constant level when so desired. However, before proceeding to a consideration of the specific means employed to acconiplish this purpose, it may be convenient to consider the elfect that variations in high exhaust will have on playing intensities.

As has previously been explained, the ditferential between regulated exhaust and high exhaust results in an upward pull on the valve 9. It, therefore, this differential is in creased by increasing the degree or" high exhaust, the upward pull on the valve is increased, and, therefore, in order that the valve may be maintained in equilil riurn, one of the forces pulling downwardly on the valve must be increased. This results because the increased upward pull on the valve tends to pull the valveaway from its seat to pern'iit an increased amount of air to be withdrawn from the regulated exhaust chest which in turn tends to increase the degree of regulated exhaust which results in a tendency to collapse the pneumatic 21 thereby increasing the tension on the regulated spring 23. It is this increased tension within the pneumatic 21 acting downwardly on the valve which balances the increased upward pull on the valve to hold the valve in equilibrium, the result being that when the degree of high exhaust is increased, the degree of regulated exhaust is also increased. As will be apparent, by reverse operation, if the degree of high means have so of pressure high, as wi l be ht be attained L been provided ti in high exhaust apparent, the sa by controlling t source of i board the high ex'ia st che ulator'bellows 201 which .5 i cation with the high exhaiu the passages 203. llhe rcsc prises a :hxed leai 20 iand 1.

position nieens of a leaf spring 206.

A valve 213 is mean. d on a valve 214. and is norinai f held in position aga the valve seat 215 by means of a coil spring 216. i LS will. be observed, free passage of atmospheric air is pernii d to the high exthe valve 213 is open.

haust c rest 14; who

hen the pump is operated to withdraw air from the high exhaust chest to reduce the pressure and create a partial vaciu. a in a well-known manner, it no .ll()\'"0l 'i-$li-.; of the valve talres place, the pump will produce the h u exhaust within its capacity. will be apparent, however, that movement o the 2H3 away from its seat will permit the flow or atnios iih'eric air into the high exhaust chest to her by reduce the deg c high exhaust. It will also be obscr exhaust in the high exhaust chest 1% w to collapse the regulatrn' pneuina against the force of its spring 206, the the exhaust in the exhaust chest 14, the greater being the collapse of the pneumatic 201.

Neglecting for the moment the specific form of connection between the bellows 201 and the valve stem 21ft, a. d 2 suining that some direct connection is present, it will be apparent that closing movement of the pneun'iatic 20l will. move the valve 213 away from its se t to admit atrno. pheric air to the high exhaust chest l i.

The effect of this action will be to maintain the pressure in the hi gh exhaust chest at a substantially constant level. It the doof exhaust tends to increase, the reg lator pneumatic 201 will tend to collapse d due to this connection with the valve stem 214-, the valve 213 will admit atmospheric air to the high exha. chest i l to thereoy tend to decrease the degree of exhaust. on-

versely, it the er-tl'iaiist the high exhaust chest 14 tends to decrease the regulator pneumatic 201 will tend to ex anl to draw the valve 218 more closely to its seat to admit atmospheric air to the exhaust chamber 2 l2, and the degree of exhaust therein will there-- by tend to be increased.

will he understood, thereto-e, that in the oi the valve 218, an etpul itllil is into position tor engagenwnt with the 'alve stem 214:. The valve stem 21% i v conveniently be pivoted as 2t 2534-. A ut step 236 is provided for the pneumatic 230 wluch is fixed to the lea-t 205 and extends over and engages the outer face of the lest 237 means of an adpistahle screw i lnmt stop 23.) is also provided for the pneumatic 231 which is fixed to the leaf 240 and extends over and engages the leaf 23%. bv means of an adjustable screw 24:1. The ertent of mo ment of each of the pneumaties and ma v be adjusted by the set screws and 211.

hen the pneumatics and 231 1n expanded condition, the limit stops 236 and 239 cause the leaf 240 to move with the i 'Z 205 of the regulator bellows 201 and transmit motion of the leal? 205 to the valv cm 214 through its pivotal connection therewith. When both of the pneumatics 280 and are in expanded condition, this movement will not be transmitted until the regulator pneumatic 201 is nearly collapsed. On the other hand, when the bellows 230 and are both collapsed. a very slight movement ot the regulator bellows cause movement of the valve steam and valve. By providingbellows 230 and 231 with diff e. t opening movements, tvo ditlerent intermediate positions of the leat 205 mav be secured in which movement thereof will be transmitted to the valve 213 In each of these positions of the rergulator bellows 201 different condition or: equil brium will be set up due to the fact th in each position the spring 206 exerts a diltlerent opening force upon the leaf 205. in its wide or posi on the spring exert. its least degree of pressure, while in its closed position the spring. being: held to a greater degree of compression. exerts a greater force.

The result of such operations on the pressure in the hiegh exhaust chest 1s will now be apparent. l Vhen the pneumatics'230 and 231 are caused to collapse, the degree of exhaust in the high exhaust chest 1.4. will be at a minimunn and conversely when the pneumatics 230 and 231 are caused to expand, the degree of exhaust in the high exhaust chest 1% will be at its highest level. When one of the pneumatics is collapsed and the other is expanded, intermediate pressures are secured in the high exhaust chest 1 1. In any one of the positions indicated the regulator bellows 201 ct course will control the valve 213 to maintain the pressure established at a. substantially constant level, and it will continue to do so until a change in the positions of the pneuinatics 230 and 231 causes a new condition of equilibrium to be set up.

Means are provided for controlling the operation of the bellows 230 and 231 automatically from the tracker bar. For this purpose, a valve block 250 is provided in which are mounted an outside valve 251 and an inside valve 252 which may be operated by diaphragms 253 and 254; respectively. An exhaust chamber 255 is provided which is constantly maintained. under exhaust by means ot the passage 256 connected to the high exhaust chestll. When the valves are in their normal ated position, the passage 257 to the pneumatic 230 is open to atmospheric air through the port 258 and the pneumatic 280 remains therefore in expanded condition. On the otl'ier hand, the passage 259 is subjected to exhaust from the exhaust chamber 255 and the pneumatic 231 therefore, is normally maintained in collapsed position.

The normal positioin therefore of the pneumatics will be as illustrated, and the normal degree of exhaust in the high exhaust chest 14 will be at the first step above its minimum. 11". under these conditions atmospheric air is admitted to the diaphragm chamber 261 through the passa g'e 262, the valve 252 will be raised cutting); off the passage of atmospheric air throuah the port 258 and allowing; suction through the passage 263 to collapse the pncu matie 230. Under these conditions the pneumatics 230 and 231 will both be collapsed and the degree of exhaust in the high exhaust chest 14twill be at a minimum.

if, under these conditions, atmospheric air is admitted to the diaphragm chamber 265 through the passage 266, valve 251 will be raised. exhaust from the chan'lber will be cut off. and atmospheric air will be allowed to enter the pneumatic 231 through the port to therebv expand the pneumatic and increase the degree ct exhaust in the high exhaust chest 1 Bv manipulation of the valves 251 and 252 through the admission of atmospherisiair to the passages 262 an d 266. the pneumaties 230 and 231 may be controlled at will to cause them to assume varying}; positions to therebv establish and maintain varvingr degrees of exhaust in the high exhaust chest 14.

Passages 262 and 266 may be connected to the tracker vents 276 and 276 in order that the valves 251 and 252 may be controlled automatically by a suitable note sheet.

The operation of the apparatus will be apparent from the foregoing description. To sum up, however, valves 251 and 252 are controlled by openings in the note sheet to operate the pneumatics 230 and 231 to cause varying pressures to be established in the high exhaust chest 14. Such pressures, when established, are maintained at a. substantially uniform level by the regulating action of the regulator bellows 2-01. In normal operation, that is with tracker vents 276 and 276 bot-h closed, the degree of exhaust may be conveniently maintained at an intermediate level in order that pressures both below and above this level may be established by proper openings in the notesheet. Such changes in pre sure being established in the high exhaust chest 1e also affect changes in playing intensities as before described. The accordion bellows 15 and its component parts a, b, c and (1, controlled by their respective valve mechanisms 17, iowever, maintain their respec tive capacities to produce step changes whatever the pressure established in the high exhaust chest may be. The step changes established, however, will vary depending upon the particular pressure established in the high exhaust chest.

The apparatus illustrated and described herein is similar in certain respects to that illustrated and described in a copending application filed by Charles F. Stoddard, March 12, 192%, Serial No. 698,599. In that application such invention as is common to the two applications is claimed generically. Herein, among other thin s, there is illustrated and described the adaptation of certain features of the aforementioned application to a different apparatus and no claim is broadly made herein to the common subject matter.

Nevertheless, the present invention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influi-xnced by the force of exhaust from said source of pneumatic power toward open position; an accordion bellows connected to said throttle valve comprising sections having different extents of movement means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; and additional pneumatic means connected to said throttle valve to maintain at said. player pneumatics the degree of exhaust established by said varying means whether one or many notes he sounded simultaneously.

2. In an automatic musical instrument having x I pneumatms and a source of pneumatic pm o in combination, a throttle valve interposed. between said player pneumatics and source of pneumatic power, and influcnccd by the force of exhaust from said source of pneumatic power toward open position; an accordion bellows connected to said throttle valve comprising sections having difiereat extents of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneuniatics; additional pneumatic means connected to said throttle valve to maintain at said. player pneumatics the degree of exhaust established by said varying means whether one or many notes he sounded simultaneously; and means for altering the force of exhaust from said source oi pneumatic power acting on said throttle valve to thereby alter the degrees of exhaustestablished and maintained by the aforesaid means.

In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influenced by the force oi exhaust from said source of pneumatic power toward open position; an accordion bellows connected to said throttle valve comprising sections having different extents of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; additionalpneumatic means connected to said throttle valve to maintain at said player pneumatics the degree of exhaust established by said varying means whether one or many notes be sounded sii'nultaneously; means for altering the :torce or" exhaust from said source of pneumatic power acting on'said throttle valve to th reby alter the degrees of exhaust established and maintained by the aforesaid means; and means to maintain the force of ex haust substantially constant at whatever level it set by said altering means.

4. In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination. a throttle valve interposed between said player pneumatios and source oi? pneumatic power, and influenced by the force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said she; an accordion bellows connected to said rigid element, comprising sections having different extents of movement; means to collapse said sections selectively to thereby vary the degrees of exhaust applied to said player pneumatics; and additional pneumatic means pivotally connected to said rigid element to maintain at said player pneumatics the degree of exhaust established by said varying means whether one or many notes are sounded simultaneously.

5. In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influenced by he force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said valve; an accordion bellows connected to said rigid element, comprising sections having ditterent extents of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; additional pneumatic means pivotally connected to said rigid element to maintain at said player pneumatics the degree of exhaust established by said varying mca :5 whether one or many notes are sound-ed simultaneously; and means for altering the :torce of exhaust from said source of pneun'iatic power acting on said throttle valve to thereby alter the degrees of exhaust established and maintained by the aforesaid means.

6. In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination, a throttle valve interposed between said player penumatics and source of pneumatic power, and influenced by the force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said valve; an accordion bellows connected to said rigid element, comprising sections having different extents of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; additional pneumatic means pivotally connected to Said rigid element to maintain at said player pneumatics the degree of exhaust established by said Varying means whether one or many notes are sounded simultaneously; means for altering the force of exhaust from said source of pneumatic power acting on said throttle valve to thereby alter the degrees of exhaustestablished and maintained by the aforesaid means; and means to maintain the iorce of exhaust substantially constant at whatever level it is set by said altering means.

7. In an automatic musical instrument having player pneumatics and a source or pneumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influenced by the force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said valve; an accordion bellows connected to said rigid element, comprising sections having different extends of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; and additional means Leeaeao pivotally connected to said rigid element to maintain at said player pneumatics the degree of exhaust established by said varying means whether one or many notes are sounded simultaneously, including a pneumatic havinga variable tension element tending to open it.

8. In an automatic musical instrument having player pneumatics and a source of penumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influenced by the force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said valve; an accordion bellows connected to said rigid element, comprising sections having different extends of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; additional means pivotally connected to said rigid element to maintain at said player pneumatics the degree of exhaust established by said varying means whether one or many notes are sounded simultaneously, including a penumatic having a variable tension element tending to open it; and means for altering the force of exhaust from said source oi? pneumatic power acting on said throttle valve to thereby alter the degrees of exhaust established and maintained by the aforesaid means.

9. In an automatic musical instrument having player pneumatics and a source of pneumatic power, in combination, a throttle valve interposed between said player pneumatics and source of pneumatic power, and influenced by the force of exhaust from said source of pneumatic power toward open position; a rigid element pivotally connected to said valve; an accordion bellows connected to said rigid element, comprising sections hav ing dil'lerent extents of movement; means to collapse said sections selectively to thereby vary the degree of exhaust applied to said player pneumatics; additional means pivotally connected to said rigid element to maintain at said player pneumatics the degree of exhaust established by said varying means whether one or many notes are sounded simultaneously, including a pneumatic having a variable tension element tending to open it; means for altering the force of exhaust from said source of pneumatic power acting on said throttle valve to thereby alter the degrees of exhaust established and maintained by the aforesaid means; and means to maintain the force of exhaust substantially constant at whatever level. it is set by said altering means.

In testimony whereof, I have signed my name to this specification this 17th day of April, 1924.

CHARLES F. STODDARD. 

